This invention relates to an athletic shoe, especially a running shoe, for running and jumping competitions having a sole made of a flexible plastic with molded projections on its running surface.
Athletic shoes of the initially noted type for track and field purposes, especially for sprint and short distances, are generally known and described and shown, for example, in the brochure "PUMA-Sportschuhe 66," pages 8 and 9, under the title of "PUMA SF-Form". These running shoes, having the special sole form SF (super-form), are extremely light because the actual running sole is provided only in areas that constitute tread areas. In the areas of the arch of the foot, the comparatively thin material of the upper is fitted to the arch of the foot. In contrast to previous constructions, these shoes are very light because relatively large amounts of sole material is saved in the area of the sole. Because of the usually continuous rubber running sole, these running shoes are very elastic. The spikes projecting downward in the forefoot area are riveted into a midsole. Therefore, this area is not very elastic and, considered separately, quite heavy.
It is known, on the basis of DE-AS 1 014 462, to leave out the midsole and, in order to save weight, to arrange the plate provided for the fastening of the spikes between two plastic plates made, for example, of polyamide. The two plastic plates are disposed between the insole and the running sole. This construction is lighter than the previously used metal plates, but it is also very inelastic.
It was found that running shoes having a running sole that, in the area of the center of the foot, is very narrow, when extreme lightness is endeavored, are very soft and can, especially in this area, be distorted easily and are, therefore, not very dimensionally stable. When the running sole is made of a harder material, the flexibility will suffer, especially in the ball area, so that peak performances cannot be achieved and an anatomically favorable fit to the foot during the treading motion is not possible.
A primary object of the present invention is, therefore, to provide an athletic shoe for field and track use, especially a running shoe, which, while being as light as possible, is optimally fitted to the anatomical conditions of the foot during the run, and offers as little resistance as possible to the natural movements. On the other hand, a good guidance and support of the foot and, at the same time, a high resistance to distortion must also be guaranteed.
This objective is achieved, in accordance with a preferred embodiment of the invention, since the running shoe, in an area of the longitudinal arch of the foot, is placed toward the outside edge of the foot and is narrowed so that the outside edge of the foot, stressed during running, is still fully supported; the running sole is provided with a reinforcement plate extending from the heel, via the narrowed part of the sole, to at least approximately before the start of the ball of the foot and being fitted onto the running sole, and since the running sole, in the area of the longitudinal arch of the foot; forms a supporting wall that extends diagonally upwardly toward the inside of the foot and is substantially fitted to the arch contour of the longitudinal arch of the foot.
Because of the known shape of the running sole, material is saved for the running sole which results in the saving of weight. By means of the arrangement of the reinforcing plate in the area of the center of the foot, i.e., in the area of the arch of the foot, reaching to the heel, the required resistance to distortion is achieved, on the one hand. On the other hand, in this area, the reinforcing plate, as well as the running sole, may be developed to be very thin so that the sole, as a whole, is at least not thicker than the previously used sole constructions. Nevertheless, the desired resistance to distortion is achieved and the low weight of the shoe is maintained. Finally, by means of the supporting wall shaped on in the area of the joint, the arch of the foot is decisively supported, especially also in the moving phases, so that corresponding arch supports, known by themselves, may possibly be eliminated. In addition, this supporting wall also contributes to the fact that the resistance to distortion of the running sole is increased significantly.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.